1. Description of the Related Art
Sweep modeling is a type of computer graphics technique that is used to generate solid three-dimensional (3-D) models (which may be referred to as extrusions, or curved extrusions) from two-dimensional (2-D) surfaces. Sweep modeling generally involves moving or “sweeping” a 2-D surface through a 3-D space. The volume swept by the path of the surface defines the 3-D model, or extrusion. In conventional sweep modeling techniques, the user first explicitly defines a space curve. Coordinate frames are formed along the space curve, and then cross sections are extruded along the space curve to generate the 3-D model. To make modifications, the user must edit or redefine the space curve. Since these conventional techniques require the user to explicitly define and manipulate the geometry such as the space curve, the user may typically need to have extensive knowledge of 3-D modeling geometry and of the sweep modeling tools to successfully apply these techniques to achieve desired results.
2. Touch and Multitouch Technologies
Conventional touch-enabled technologies (e.g. a computer touchpad, ATM screen, etc) recognize only one touch point. Multitouch is a technology that provides hardware and software that allows computer users to control various applications via the manipulation of multiple digits on the surface of (or, for some devices, proximate to) a multitouch-enabled device. Multitouch technology generally consists of a touch-enabled device (referred to as a multitouch device) such as a touch-sensitive display device (computer display, screen, table, wall, etc.), touchpad, tablet, smartphone, camera, etc., as well as software that recognizes multiple, substantially simultaneous touch points on the surface of the multitouch device. A multitouch device may be a direct or absolute touch device in which the touch points are applied directly to a display device, or an indirect or relative touch device in which the touch points are applied to a pad or tablet and mapped to a display device.